A collaboration between New Castle County officials and Massachusetts-based Biobot Analytics estimates positive cases of COVID-19 above the C&D Canal could be 15 times higher than what’s been confirmed by the state.

Biobot, which involves researchers from MIT, Harvard and Brigham and Women’s Hospital, uses flow rate and population data along with published rates of the virus shedding in stool to come up with an estimate. For New Castle County, Biobot detected more than 40,000 copies of the coronavirus per liter of sewage from an April 15 sample. Using Biobot’s formula, it was estimated 3 percent of the population, or 15,200 people, have or have had the virus.

Biobot officials say in a press release that the rate they estimate is much higher than the state’s confirmed statistics because testing remains limited and likely does not represent the entire infected population. Some COVID-19 patients are asymptomatic or have mild symptoms and do not seek testing, the press release says.

“The idea behind our technology is simple: everybody pees (and poops, hopefully) every day,” the company wrote in a blog on its website. “When you use the toilet, you’re excreting valuable health information. The bacteria, viruses, and chemical metabolites that you shed provide a readout of your health.”

It’s like going to the doctor and giving a urine or stool sample for diagnostic tests, but instead of measuring just one individual, Biobot says it can measure an entire community.

Gov. John Carney said he had just learned about this testing during an April 24 press conference. He said it was not done in collaboration with the state and is not a widely accepted approach to accurately identify cases.

“We’re trying to follow the science that public health officials are working on today,” he said. “We are taking our lead from CDC and the White House task force, and this is not any science I’ve heard of from my colleagues across the country.”

As of now, Sussex County will not pursue the wastewater test, said Chip Guy, the county’s director of communications.

“The sample in New Castle County was for one plant only,” Guy said. “To give a more comprehensive picture in Sussex would require testing from eight-plus facilities, both county and municipal.”

Lewes Board of Public Works President Pres Lee said he would be open to having a sample from the facility on American Legion Road sent to the group for testing if they were willing to work with BPW. He said he would research further.

Kevin Williams, public works director in Rehoboth Beach, said Rehoboth has not been asked to participate in such testing, but would be willing to discuss participation if a group approached the city.

Biobot is working with more than 150 facilities in 30 states. While there is a waitlist, Biobot is encouraging cities and municipalities to continue to sign up. The plan is to scale the operation to more than 10,000 wastewater facilities. Biobot is offering the service pro bono. 

Prior to the coronavirus crisis, Biobot developed technology to measure traces of drugs in sewers to help researchers analyze patterns of ongoing drug use and detect emerging public health epidemics.